The EU has!
When will speed limiters be mandatory?
From 6 July 2022, all new cars will need to have a speed limiter device fitted.
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Though I am failry happy that drivers should be encouraged to drive within speed limits, there are issues. Imagine driving someone to hospital as an emergency - in the middle fo the night with no traffic - and still having to stick to low limits. So some flexibility is required.
There is always the possibility that if traffic actually obeyed speed limits, some could be allowed to rise.
Maybe we'll actually use non-symmteric limits more often? Even as simple as 40mph on roads going out of town and 30mph coming in - at least at the periphery of the town.